My son motion lights , while not being home house was robbed what can he do?

So he got robbed...install a monitored security system...or just wait for the next time.  Motion lights and other things are deterrents.  The only useful thing here is monitored security....where they send out the local cops if something happens.  

You can get timers to install in the house & set them so that the lights come on and go off at different times during the day/evening.

Install an alarm. There are many that use WiFi and do not require any wiring.